The present invention relates to a gas-processing agent for gas purification, which oxidizes carbon monoxide and/or hydrogen contained in a compressed gas in the presence of oxygen, and then removes the simultaneously produced carbon dioxide and/or water vapor by means of adsorption. In particular, the present invention relates to a gas processing agent for gas purification used in a gas purifier which oxidizes and removes carbon monoxide and/or hydrogen from the compressed air, in a feed gas purification system of a cryogenic air separation plants which separates and produces highly-purified nitrogen, oxygen and the like by compressing air, removing a small amount of impurities contained therein, cooling and performing rectification by liquefaction. In addition, the present invention relates to a manufacturing method of a processing agent for gas purification and a gas purification method, a gas purifier and a gas purification apparatus using the gas processing agent.
Conventionally, alumina catalyst impregnated with platinum or alumina catalyst impregnated with palladium and the like have been used as a gas processing agent for purifying a feed air in a cryogenic air separation plants for producing highly-purified nitrogen etc. It is essential to use these catalysts at a temperature within a range of 100xcx9c250xc2x0 C. for oxidizing and removing carbon monoxide and/or hydrogen which are generally contained in the atmosphere at a content of 1 to several ppm, and, in order for capturing carbon dioxide and water vapor generated by oxidation reaction, to cool a gas after the reaction and then remove them using an adsorbent. For this reason, a great quantity of air and catalyst have to be heated and cooling equipments and adsorbents have to be used for capturing carbon dioxide and water vapor, which are very uneconomical.
As an example of a gas purification using a catalyst around the room temperature, Japanese patent laid-open publication No. 4-219111 discloses a method for manufacturing a highly-purified gas by using a catalyst at a reaction temperature within a range of 4.4xcx9c50xc2x0 C. In this method, at first water vapor is removed from air flow containing carbon monoxide, hydrogen, carbon dioxide and water vapor by an adsorbent, then carbon monoxide is oxidized to carbon dioxide by a mixture of manganese oxide and copper oxide, then hydrogen is oxidized to water vapor by using palladium catalyst, and then carbon dioxide and water vapor are adsorbed and removed by providing an adsorbent in the rearmost end portion of the catalyst. However, each separate catalyst layer is required for the oxidation reaction of carbon monoxide and for the oxidation reaction of hydrogen, and in addition, another adsorbent layer is need to be provided in the rear end portion of catalyst layer for removing carbon dioxide and water vapor, which are generated in oxidation reaction, from a processing gas.
Similarly, Japanese patent laid-open publication No.10-85588 reports an example of a gas purification performed by using a catalyst at a temperature within a range of 0xcx9c100xc2x0C. This method is to remove carbon monoxide, hydrogen, carbon dioxide and water vapor contained in gas, by solely or jointly using each catalyst in which gold impregnated metal oxides or alkaline earth metal hydroxides or palladium is impregnated in adsorbents with a good adsorption ability of carbon dioxide and water vapor in the presence of oxygen. However, as the catalytic components are impregnated in the adsorbent itself with a good adsorption ability of carbon dioxide and water vapor, the carbon monoxide and water vapor generated by the oxidation of carbon monoxide and hydrogen, adsorbed and accumulated in the catalytic active site, hinder the carbon monoxide and hydrogen in the gas flow from being adsorbed to the catalytic active site and further obstruct the catalytic reaction. Therefore, there is a problem that a duration of an oxidation ability of carbon monoxide and hydrogen in the gas flow do not continue for a long time.
Under the above circumstances, a gas purification processing agent having a dual function, which oxidizes carbon monoxide and/or hydrogen at the temperature within the range of 0xcx9c100xc2x0 C. and adsorbs and removes the generated carbon dioxide and/or water vapor at the same time, catalytic oxidation ability and oxidation ability of which continues for a long time, has been demanded.
The present invention has been developed to solve the above-mentioned problems and has an object of providing a gas processing agent which can remove carbon monoxide, hydrogen, carbon dioxide and water vapor contained in gas at the same time, keep a high adsorption ability and catalytic oxidation activity and have a long life time, a manufacturing method therefore, a gas purification method, a gas purifier and a gas purification apparatus.
The present inventors have conducted significant studies to solve the above-mentioned problem and as a result, have found out a gas processing agent with a long life time, which can oxidize carbon monoxide(CO) and/or hydrogen(H2) at a temperature within a range of 0xcx9c80xc2x0C. in the presence of oxygen and simultaneously remove the generated carbon dioxide(CO2) and water vapor(H2O), thereby completing the present invention.
That is, the present invention provides a gas processing agent comprising a catalyst made of inorganic porous materials containing at least an element selected from a group consisting of platinum, palladium, ruthenium, rhodium or the oxides thereof, and an adsorbent.
Further, the present invention provides a manufacturing method of the gas processing agent, a gas purification method using the gas processing agent, a gas purifier and a gas purification apparatus.